PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics Endocrine therapy: Not specified Radiotherapy: No prior extensive radiotherapy to more than 30% of bone marrow (e.g., whole pelvis or half of spine) No concurrent radiotherapy for ovarian cancer Surgery: At least 2 weeks since prior surgery,except for insertion of central venous access device, and recovered Other: At least 4 weeks since other anticancer therapy and recovered Concurrent folic acid in a nutritional supplement allowed except within the 24 hours before and after ZD9331 dosing No other concurrent study drugs No other concurrent systemic therapy for ovarian cancer